What information can be accessed by Dennis in an on-path attack?

In an on-path attack, also known as a man-in-the-middle attack, an attacker positions themselves in the communication pathway between two parties. This allows the attacker to intercept, modify, and view traffic exchanged between those parties.

When we consider what information Dennis can access through this type of attack, option B stands out because it reflects the nature of on-path attacks. Dennis can capture and inspect all traffic that is intended for remote systems, as he can relay or modify messages between the sender and receiver without either party realizing it. This includes sensitive information, authentication credentials, and other data being exchanged.

The other options do not accurately describe the capabilities in an on-path attack as effectively. Therefore, option B accurately characterizes the extensive access that an attacker like Dennis would have in this scenario.